As air-conditioning apparatuses, such as multi-air-conditioning apparatuses for buildings, there has been a circuit for performing liquid injection to a portion between a high-pressure liquid pipe to the compressor of a refrigeration cycle in order to lower a discharge temperature of a compressor or an air-conditioning apparatus which is capable of controlling the discharge temperature to a preset temperature, without depending on an operation state (see, for example, Patent Literature 1).
Furthermore, there has also been an air-conditioning apparatus which is capable of injecting a liquid-state refrigerant (liquid refrigerant) in a high-pressure state in a refrigeration cycle to a suction side of a compressor during a cooling operation and during a heating operation (see, for example, Patent Literature 2).
Furthermore, there has also been an air-conditioning apparatus which includes a subcooling heat exchanger on a refrigerant outflow side of a condenser, controls the flow rate of a refrigerant which is caused to flow to the subcooling heat exchanger, and controls the discharge temperature of a compressor (see, for example, Patent Literature 3).